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Abstract:

The present disclosure provides various systems and methods for inducing
cutaneous sensations by delivering electromagnetic radiation to directly
or indirectly excite neural tissue. An electromagnetic radiation source,
such as one or more infrared lasers, may be used to transcutaneously
excite neural tissue. The excited neural tissue may be interpreted by the
user's nervous system as cutaneous sensations. Accordingly, a system as
described herein may be used to induce sensations to allow actual
cutaneous sensations to be simulated. A system for inducing a cutaneous
sensation via transcutaneously focused electromagnetic radiation may be
incorporated in a display to provide cutaneous sensation feedback or used
as a separate accessory component associated with a display. Numerous
additional applications and variations are provided herein.

Claims:

1. A system configured to induce a cutaneous sensation in a user of an
electronic device based upon a tactile application executable on the
electronic device, the system comprising: a stimulation system configured
to generate an output operable to excite neural tissue; an interface
component configured to direct the output of the stimulation system onto
a target area of skin of the user; and a controller configured to
generate a control signal to cause the stimulation system to modify one
or more characteristics of the output of the stimulation system in order
to induce a cutaneous sensation based upon a tactile application
executable on the electronic device.

2. The system of claim 1, wherein the interface component is further
configured to direct the output of the stimulation system onto the target
area while the target area is in physical contact with the interface
component.

3. The system of claim 1, wherein the interface component is further
configured to direct the output of the stimulation system onto the target
area while the target area is physically separated from the interface
component.

4. The system of claim 1, wherein the electronic device comprises a
computer and the interface component comprises a mouse.

5. The system of claim 4, wherein the mouse comprises a control surface,
and the target area comprises a finger pad of a user that interacts with
the control surface.

6. The system of claim 4, wherein the control surface comprises one of a
button, a touch pad, and a track pad.

7. The system of claim 1, wherein the electronic device comprises a
computer and the interface component comprises a keyboard.

8. The system of claim 1, further comprising a display component, the
interface component being distinct from the display component, and
wherein the controller is configured to modify one or more
characteristics of the output of the stimulation system based on an
object on the display component.

9. The system of claim 8, wherein the sensation corresponds to an object
appearing on the display component.

10. The system of claim 1, wherein the electronic device comprises one of
a telepresence medicine device, a gaming device, a tablet computer
device, a telephone device, an electronic Braille display device, an
industrial control station, entertainment system, and an electronic
surgical control device.

11. The system of claim 1, wherein the system further comprises: a
thermal feedback system configured to measure a temperature associated
with the target area; and wherein the controller is configured to
dynamically control the stimulation system to maintain the temperature
below a threshold temperature.

12. The system of claim 1, wherein the output of the stimulation system
comprises one of infrared electromagnetic radiation and visible
electromagnetic radiation

13. The system of claim 1, wherein the stimulation system comprises a
laser emission system.

14. A method for inducing a cutaneous sensation in a user of an
electronic device, the method comprising: executing a tactile application
on an electronic device; generating, using an stimulation system
associated with the electronic device, an output operable to excite
neural tissue; directing the output of the stimulation system onto a
target area of skin of a user using an interface component; and
generating a control signal to cause the stimulation system to modify one
or more characteristics of the output of the stimulation system in order
to induce a cutaneous sensation based upon the tactile application
executing on the electronic device.

15. The method of claim 14, wherein directing the output of the
stimulation system onto the target area occurs while the target area is
in physical contact with the interface component.

16. The method of claim 14, wherein directing the output of the
stimulation system onto the target area occurs while the target area is
physically separated from the interface component.

17. The method of claim 14, further comprising: displaying an object on a
display component; and wherein the sensation corresponds to the object
displayed on the display component.

18. The method of claim 14, wherein the electronic device comprises one
of a telepresence medicine device, a gaming device, a tablet computer
device, a telephone device, an electronic Braille display device, an
industrial control station, and an electronic surgical control device.

19. The method of claim 14, further comprising: measuring a temperature
associated with the target area; and wherein the controller is configured
to dynamically control the stimulation system to maintain the temperature
below a threshold temperature.

20. The system of claim 1, wherein the output of the stimulation system
comprises one of infrared electromagnetic radiation and visible
electromagnetic radiation.

[0002] The present disclosure is directed to systems and methods for
directly or indirectly exciting neural tissue using electromagnetic
radiation. More particularly, the present disclosure is related to
stimulation of neural or other excitable tissues using electromagnetic
radiation for inducing cutaneous sensations.

BRIEF SUMMARY

[0003] According to various embodiments, a system for inducing-cutaneous
sensations, may comprise an electromagnetic radiation emission system
configured to emit electromagnetic radiation suitable for directly or
indirectly exciting neural tissue. The system may also include an
electronic display configured to display a graphical user interface and a
detection system configured to detect a point of contact (such as a
finger contact) with the display. A controller configured to transmit a
control signal to the electromagnetic radiation emission system to cause
the electromagnetic radiation emission system to direct electromagnetic
radiation at the contact detected by the detection system to directly or
indirectly excite neural tissue associated with the contact in order to
induce a cutaneous sensation. According to some embodiments, the
electromagnetic radiation emission system may further comprise at least
one focusing element controllable for selectively focusing the
electromagnetic radiation emitted by the electromagnetic radiation
emission system. Transcutaneously focused electromagnetic radiation may
include single or multiple beams of electromagnetic radiation coincident
at a focal point. Alternatively, a splitting element may be utilized in
some embodiments in order to direct electromagnetic radiation from one
source of electromagnetic radiation to a plurality of points of contact.
Another embodiment would be a single source of electromagnetic radiation
emission that is redirected or switched by the controller to individual
fiber optic lines (e.g. an optical switch), which are spatially arranged
to allow for specific illumination/irradiation at specific points on the
user. Finally, some embodiments may incorporate multiple sources of
electromagnetic radiation that may be selectively directed toward
multiple points of contact.

[0004] The system may further comprise a storage medium containing a
library of cutaneous sensations, each of which may be defined by a set of
characteristics of the electromagnetic radiation. The controller may be
configured to modulate the characteristics of the electronic radiation
emitted by the electromagnetic radiation emission system to induce a
specific cutaneous sensation. These individual or pre-defined sensations
can also be combined and tailored via the controller to create unique
cutaneous sensations.

[0005] At least one of the cutaneous sensations may be defined by a set of
characteristics of the electromagnetic radiation in at least two
locations in the neural tissue separated by more than a two-point
discrimination region. The controller may be configured to modify or
modulate one or more characteristics of the electromagnetic radiation
emitted by the electromagnetic radiation emission system to induce a
cutaneous sensation corresponding to an object displayed on the graphical
user interface at the location of the contact with the electronic
display. According to some embodiments, the characteristics of the
electromagnetic radiation modified or modulated by the controller may
include pulse width, pulse repetition rate, shape, amplitude, fluence,
depth, frequency, location(s), spot size, wave shape, duty cycle,
rasterization patterns, and the like.

[0006] The electromagnetic radiation emission system may comprise
Light-Emitted Diodes (LEDs) or various forms of laser sources, including
edge-emitting and surface emitting semiconductor lasers for example, and
nonlinear frequency conversion of these laser sources. Of course,
according to various embodiments, other types of visible and
electromagnetic radiation sources may also be utilized.

[0007] The electronic display may be a touch screen electronic display,
and the detection system may utilize a touch screen digitizer or the like
of the touch screen electronic display to detect the contact and
determine the point of contact or area of contact with the user. The
electromagnetic radiation emission system may be part of a moveable stage
configured to move relative to the plane of the electronic display, and
the controller may be configured to control the movement of the stage to
direct the electromagnetic radiation to the contact detected by the
detection system. The stage may comprise at least one magnet, and the
controller may be configured to control the movement of the stage
relative to the plane of the electronic display using a series of
electromagnets proximate at least two edges of the electronic display.
Alternatively, other forms of mechanical actuation may be utilized to
reposition the moveable stage. The moveable stage will allow for mounting
one of a mirror(s) and a focusing element(s) such as a lens that can
direct the incoming electromagnetic radiation from the perimeter of the
display to perpendicular to the plane of the display and into the point
of user contact.

[0008] Alternatively, the electromagnetic radiation emission system may be
configured to direct the electromagnetic radiation to the point of
contact detected by the detection system via the stage via fiber optic
cable mounted to a moveable stage. The controller may be configured to
cause the electromagnetic radiation emission system to transcutaneously
focus electromagnetic radiation at the contact using a procession pattern
bounded by a two-point discrimination region.

[0009] The system may further comprise a sub-threshold electrical
stimulation system configured to electrically stimulate a portion of the
user. According to some embodiments, the electrical stimulation system is
used to elicit electrical stimulation to achieve a subthreshold value
that can later use electromagnetic radiation to achieve the threshold and
achieve sensation. The controller may be further configured to adjust the
fluence of the electromagnetic radiation based on calibration results.
For example, the calibration results may define a minimum energy density
to induce a cutaneous sensation in the contact. The calibration results
may be obtained from a calibration phase, performed by directing
electromagnetic radiation of various fluences at the point of contact,
receiving feedback from a user indicating which of the electromagnetic
radiation pulses induced a cutaneous sensation in the contact; and
associating a minimum energy density to induce a cutaneous sensation with
the lowest fluence indicated by the user as having induced a cutaneous
sensation.

[0010] The system may further comprise a thermal feedback system
configured to measure a temperature associated with the contact, and the
controller may be configured to dynamically control the electromagnetic
radiation emission system to only deliver the appropriate fluence to
achieve the desired stimulation. According to one embodiment the
temperature of the finger or other body part is determined by a
thermistor, or the like, to provide the control system with an indication
of the skin temperature. According to another embodiment, the temperature
of the glass is maintained at a certain known temperature using feedback
from an embedded thermistor, or the like, to provide an indication of the
glass temperature.

[0011] The thermal feedback system may comprise a non-contact infrared
thermometer, a thermistor, and/or a thermocouple.

[0012] The system for inducing cutaneous sensations may be implemented on
a user interface component instead of or in addition to a display. A
discrete user interface component may be associated with a display in
some embodiments. The user interface component may comprise a track pad
or a keyboard or a mouse key or any portion thereof. According to some
embodiments the user interface component may comprise an enclosure, and
the enclosure may be configured to receive at least one finger (or other
portion of the user, such as a hand) within the enclosure. The enclosure
may comprise a glove configured to enclose two or more fingers, a finger
wrap configured to receive a single finger, or a hand enclosure
configured to receive a hand. According to one embodiment, a finger wrap
or finger sleeve may include embedded fiber optic lines. An optical
switch may be used to deliver electromagnetic radiation to a target area.
Further, such embodiments may be configured to deliver a rasterized
pattern of electromagnetic energy in order to stimulate multiple target
areas.

[0013] The user interface component may be associated with a display, and
the controller may be configured to modify one or more characteristics of
the electromagnetic radiation emitted by the electromagnetic radiation
emission system to induce a cutaneous sensation corresponding to an
object displayed on the display. The system may be integrated into a
peripheral computing device configured to allow a user to provide input
to a computing device, and the user interface component may comprise a
surface of the peripheral device. The peripheral computing device may
comprise one of a computer mouse and a computer keyboard, and the user
interface component comprises a surface of a button.

[0014] In one embodiment, a system for communicating visual information
via cutaneous sensations may comprise an imaging device configured to
image at least one object; an electromagnetic radiation emission system
configured to emit electromagnetic radiation suitable for directly or
indirectly exciting neural tissue. The system may further include an
interface component configured to deliver electromagnetic radiation to a
target area of a user's skin and a controller configured to control
operation of the electromagnetic radiation emission system. The
controller may map at least one object imaged by the imaging device to a
cutaneous sensation and transmit a control signal to the electromagnetic
radiation emission system to cause the electromagnetic radiation emission
system to deliver electromagnetic radiation at the point of contact to
directly or indirectly excite neural tissue and thereby induce a
cutaneous sensation at the point of contact.

[0015] In another embodiment, a multi-layer display configured to induce
cutaneous sensations may comprise a touch screen digitizer layer or the
like configured to detect a point of contact with a user. The multi-layer
display may also include an electronic display layer configured to
display objects; a spatial light modulator (SLM) layer configured to
dynamically focus and steer electromagnetic radiation; a VCSEL and
lenslet array layer configured to selectively emit electromagnetic
radiation suitable for exciting neural tissue. A controller may be
configured to control the SLM layer and the VCSEL and lenslet array layer
to deliver electromagnetic radiation at the point of contact to thereby
directly or indirectly excite neural tissue to induce a cutaneous
sensation at the point of contact.

[0016] A method for inducing cutaneous sensations may comprise displaying
graphical information on an electronic display; detecting a point of
contact with a user on the display; and transcutaneously focusing and
steering electromagnetic radiation at the contact of the finger to excite
neural tissue in the finger to induce a cutaneous sensation.

[0017] Various methods are also disclosed herein for inducing cutaneous
sensations. Such methods may include displaying a graphical user
interface on an electronic display and detecting a point of contact of a
finger on a haptic feedback surface associated with the electronic
display. Further the method may include generating a control signal to
cause an electromagnetic radiation emission system to deliver
electromagnetic radiation. In response to the control signal,
electromagnetic radiation may be delivered at the point of contact to
directly or indirectly excite neural tissue in the finger and thereby
induce a cutaneous sensation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Non-limiting and non-exhaustive embodiments of the disclosure are
described herein, including various embodiments of the disclosure
illustrated in the figures listed below.

[0019]FIG. 1 illustrates a block diagram of a system for exciting tissue
using electromagnetic radiation, according to certain embodiments.

[0020]FIG. 2 illustrates a simplified embodiment of a system for
delivering electromagnetic radiation onto a finger of a user, according
to certain embodiments.

[0021]FIG. 3 illustrates a simplified embodiment of multiple
electromagnetic radiation beams transcutaneously coincident within a
finger of a user, according to certain embodiments.

[0022]FIG. 4 illustrates a display associated with a system for inducing
cutaneous sensations via transcutaneously focused electromagnetic
radiation, according to certain embodiments.

[0023]FIG. 5A illustrates a touch screen configured to induce cutaneous
sensations in a user's finger by delivering electromagnetic radiation to
a point of contact with the user, according to certain embodiments.

[0024]FIG. 5B illustrates an accessory component configured to induce
cutaneous sensations in a user's finger while using a display by
delivering electromagnetic radiation to a point of contact between the
accessory and the user, according to certain embodiments.

[0025] FIG. 5C illustrates a conceptual representation of an
electromagnetic radiation delivery system including a single
electromagnetic radiation source that may be incorporated into a finger
sleeve or other device, according to certain embodiments.

[0026]FIG. 5D illustrates a conceptual representation of an
electromagnetic radiation delivery system 580 including a plurality of
electromagnetic radiation sources that may be incorporated into a finger
sleeve or other device, according to certain embodiments.

[0027]FIG. 6A illustrates an embodiment of a moveable stage for
transcutaneously rastering electromagnetic radiation to excite tissue,
according to certain embodiments.

[0028]FIG. 6B illustrates another embodiment of a moveable stage for
transcutaneously rastering electromagnetic radiation to excite tissue,
according to certain embodiments.

[0030] FIG. 8 illustrates an electro-optical system for inducing cutaneous
sensations, including an electrical stimulation system and a system for
transcutaneously focusing electromagnetic radiation, according to certain
embodiments.

[0031] FIG. 9 illustrates a schematic of an initial user calibration
procedure of a device including an electromagnetic radiation stimulation
system for inducing cutaneous sensations.

[0032]FIG. 10 illustrates a block diagram of a system for inducing
cutaneous sensations using electromagnetic radiation including a thermal
feedback system, according to certain embodiments.

[0033]FIG. 11 illustrates a system integrated within a peripheral device
of a computer for inducing cutaneous sensations using electromagnetic
radiation, according to certain embodiments.

[0034] FIGS. 12A-C illustrate three embodiments for directing
electromagnetic radiation to a point of contact using electromagnetic
radiation within a surface, according to certain embodiments.

[0035]FIG. 13 illustrates an example of a display incorporating a system
for inducing cutaneous sensations using electromagnetic radiation,
according to certain embodiments.

[0036] FIG. 14A illustrates a schematic of a relatively thin fluid layer
configured to provide ocular protection from electromagnetic radiation
that may be used to induce haptic sensations, according to certain
embodiments.

[0037]FIG. 14B illustrates a finger depressing the relatively thin fluid
layer, thereby allowing electromagnetic radiation to penetrate the fluid
layer and induce a cutaneous sensation in the finger of the user,
according to certain embodiments.

[0038]FIG. 15A illustrates an embodiment of a display incorporating a
system for inducing cutaneous sensations using electromagnetic radiation
and an array of lenslets and/or VCSELs, according to certain embodiments.

[0039]FIG. 15B illustrates an embodiment of a display, in which
collimated electromagnetic radiation traverses a transmissive spatial
light modulator layer.

[0040]FIG. 15c illustrates an embodiment of a display including a spatial
light modulating layer, which may impose a grating or dot pattern for
scanning stimulation spots and rasterization schemas.

[0041] In the following description, numerous specific details are
provided for a thorough understanding of the various embodiments
disclosed herein. The systems and methods disclosed herein can be
practiced without one or more of the specific details, or with other
methods, components, materials, etc. In addition, in some cases,
well-known structures, materials, or operations may not be shown or
described in detail in order to avoid obscuring aspects of the
disclosure. Furthermore, the described features, structures, or
characteristics may be combined in any suitable manner in one or more
alternative embodiments.

DETAILED DESCRIPTION

[0042] According to various embodiments, electromagnetic radiation may be
used to induce apparent cutaneous sensations in a user. Accordingly, the
various embodiments of the systems described herein are configured to
induce cutaneous sensations through the application of transcutaneous
electromagnetic radiation. In some embodiments, mechanical deformation of
the skin is used to produce tactile sensation. Challenges associated with
using mechanical devices for creating haptic sensations may include the
inertia of moving parts and the difficulty in miniaturization to create
sufficiently high resolution. In other embodiments, direct electrical
stimulation of tissue may be used. However, electrical stimulation often
has poor spatial resolution due to current spreading between electrodes.

[0043] Electromagnetic radiation, such as light emitted in the infrared or
visible spectrum, may be applied to a user's skin in order to stimulate
neural tissue in the skin and thereby induce action potentials, either
directly or indirectly, at the site of irradiation. Irradiation of the
skin that induces, either directly or indirectly, action potentials in
the peripheral nervous system which are highly spatially selective, and
may thus achieve high resolution and may be utilized in connection with
many applications.

[0044] Lasers may be used in ablative and non-ablative applications.
Ablative laser systems may impart sufficient energy to the tissue so that
some portion of the tissue architecture may be destroyed or otherwise
transformed. For example, ablative lasers may be used in surgery to
replace or supplement the use of scalpels and cautery instruments.
Ablative lasers may also be used in aesthetic dermatology to encourage
dermal remodeling. At somewhat lower energies, both ablative and
non-ablative, systems may be adapted for port wine stain removal using
photocoagulation techniques that selectively destroy the excessive
accumulation of blood vessels. Non-ablative laser technologies may apply
lower energies or fluences than ablative lasers. Non-ablative lasers may
be used to promote wound healing, relax sore muscles, and potentially
alter cellular function in various ways. Low-level light therapy (LLLT)
devices have applications in medical and veterinary uses, as well as in
the field of dentistry. According to various embodiments described
herein, electromagnetic radiation may be used at wavelengths at energies
that do not cause tissue damage. According to some embodiments, the
energy density utilized by some embodiments may be higher than that of
traditional LLLT devices.

[0045] Electromagnetic radiation suitable for exciting neural tissue,
either directly or indirectly, may include specific wavelengths or a
range of wavelengths, according to various embodiments. The application
of electromagnetic radiation to nervous tissue may elicit action
potentials. The system may utilize a wide range of one or more different
wavelengths between approximately 400 nanometers (nm) and 8000 nm,
including but not limited to 650, 808, 850, 860, 885, 915, 940, 980,
1064, 1120, 1310,1450, 1470, 1490, 1495, 1540, 1550, 1850, 1862, 1870,
2000, 2100, 2120, 3000, 4000, and 6000 nm. The present disclosure
contemplates several different embodiments of the device with different
electromagnetic radiation sources. For example, one embodiment uses a
laser as the electromagnetic radiation source. In another embodiment, the
electromagnetic radiation source may utilize one or more LEDs. In another
embodiment, a flash tube broad-spectrum light source may be utilized. Any
of a wide variety of electromagnetic radiation sources capable of
delivering electromagnetic radiation at a sufficient power density may be
utilized. Some embodiments may utilize a single wavelength source, filter
all but a single wavelength of a broad-spectrum source, and/or utilize a
multi-wavelength source of electromagnetic radiation. In some
embodiments, a filter may be placed at any point between the
electromagnetic radiation source and the tissue to be stimulated.

[0046] The present disclosure provides various embodiments of systems and
methods for inducing cutaneous sensations using transcutaneously
delivered electromagnetic radiation. As used herein, the terms
electromagnetic radiation represents the breadth of the electromagnetic
spectrum, as applicable to the present disclosure. In various
embodiments, tissue may be transcutaneously irradiated for the purpose of
simulating the sensations of cutaneous touch. The cutaneous sensations
may represent physical traits of actual objects at a remote location, or
can represent simulated objects.

[0047] For example, a system for inducing cutaneous sensations using
transcutaneously delivered electromagnetic radiation may be used for any
number of tactile applications, such as, but not limited to, telepresence
medicine, compact electronic Braille displays, virtual product online
shopping, representing virtual and physical objects and drawings in
computer generated images and computer aided drafting (CAD), for touch
screen feedback, control feedback, and/or entertainment and gaming
devices. The use of electromagnetic radiation for stimulating neural
tissue may be more responsive than a mechanical system and may provide
higher spatial resolution than a purely electrical system. In addition,
the lack of moving parts may result in higher reliability and lower
maintenance of the system.

[0048] In some embodiments, transcutaneously delivered electromagnetic
radiation may be used to induce cutaneous or subcutaneous sensations for
use in less-than-lethal weapons. Less-than-lethal weaponry is widely used
by military and police forces for crowd control and other situations
where slowing or immobilizing a person is preferable to causing serious
injury or death. Transcutaneous application of electromagnetic radiation
may be used to cause a sensation on or beneath the skin. For example, a
less-than-lethal weapon utilizing transcutaneously applied
electromagnetic radiation may be used to cause sensations associated with
burning, pressure, scraping, cutting, and/or other unpleasant or painful
sensations that may deter a person from a particular course of conduct.
Such a system may be configured to cause no damage, or minimal damage, to
tissue. Rather, the system may simply induce sensations in the brain as
being extremely unpleasant or injurious.

[0049] In some embodiments, a patch or plate, which is adhered to the
skin, may be used to transmit electromagnetic radiation to/through the
skin. Such a device may be adapted to communicate tactile information to
the wearer discretely and/or silently. Such a system may be used in
silent military applications.

[0050] In some embodiments, a system configured to induce cutaneous
sensations via transcutaneously focused electromagnetic radiation may be
used to induce pleasant sensations as well. For example, a system may be
adapted to comfort and/or calm premature infants in incubators. The
system may simulate human contact without exposing them to the
contamination that the incubator intends to avoid. In some embodiments
such a patch could provide comfort to older patients as well. Those
afflicted with depression, seasonal affective disorder, or other mental
illness that have shown response to vagal nerve stimulation. Cutaneous
stimulation on the proper body parts may also help alleviate some of
their symptoms. Also, in autism and other developmental disorders many
individuals engage in autostimulation behaviors. In some of these cases
the autostimulation behavior can cause serious injury. Optical
stimulation of these patients may prove to satisfy the desire for
stimulation in a less injurious manner.

[0051] A system may utilize a control program to control the application
of electromagnetic radiation. For example, the electromagnetic radiation
may be directed to the tissue in such a way that only a small portion of
the tissue is irradiated. The tissue may be excited in such a way that
the brain perceives it as mechanical stimulation. The amount of energy
imparted to the tissue may be the minimum necessary to reliably and
reproducibly elicit the desired response. In some embodiments, the
control program may be calibrated for a set of users and/or a specific
user. In some embodiments, a feedback mechanism may be used to
dynamically adjust the output. For example, the control program may be
initially calibrated and then dynamically adjust the amplitude, focus,
rasterization pattern, and/or other attributes of the electromagnetic
radiation based on a thermal sensor to protect the skin from damage.

[0052] The control program may utilize an infrared imaging device or other
temperature probe to detect the surface temperature of the skin and make
appropriate adjustment to the stimulation protocol. In another embodiment
the feedback may be quasi-closed loop and may be accomplished by
incorporating calculations from a proprietary computer simulation, and/or
empirical data collected from various human or phantom tissue testing in
the form of a look-up table where the stimuli delivered are known to
change the tissue temperatures and subsequent stimuli are adjusted
accordingly.

[0053] Tactile and/or other cutaneous sensations may be created by the
activation of mechanoreceptors that are normally triggered. These
receptors are distributed unequally in different areas of the skin. In
order to selectively stimulate a different number of receptors, neuronal
axons, or other excitable tissues the application of optical energy may
be applied in a controlled manner.

[0054] In some embodiments, a plurality of optical focusing devices may be
used to direct electromagnetic radiation to the tissue. This may be
accomplished through the use of any combination of lenses, mirrors, fiber
optics, and/or other electromagnetic manipulation materials. The incident
electromagnetic radiation may be focused to provide a spot size, large
enough to assure stimulation of excitable tissues, while remaining small
enough that collateral heating of non-excitable tissues are minimized.
The beam shape of the electromagnetic radiation may be controlled to
limit collateral heating of non-excitable tissues. For example, a highly
converging beam with short focal region may be focused at or beneath the
skin surface. In other embodiments, the electromagnetic radiation may
comprise several beams of electromagnetic radiation focused
transcutaneously. Focusing electromagnetic radiation may include the
utilization of optical components such as lenses and/or mirrors, and/or
the usage of coincident beams of electromagnetic radiation. The focal
point(s) may be at a location(s) within the tissue where electromagnetic
radiation can be used to produce neural excitation.

[0055] In some embodiments, to avoid overheating of a single area of
tissue, beam procession may be used within a small area. The procession
of the beam may be confined to an area where different stimuli are
spatially indistinguishable by the brain. In other words, the area of
confinement for the procession may be experienced by the user as
stimulation of the same point on the skin. Accordingly, two-point
discrimination may vary depending upon which area of a user's body is
irradiated.

[0056] Accordingly, by rasterizing the applied beam of electromagnetic
radiation, the system may stimulate many points on the skin
simultaneously, or nearly simultaneously, and/or may reduce cutaneous
and/or subcutaneous thermal buildup. In one embodiment, the beam is
scanned or rastered through the use of a device, such as a
galvanometer-based optical scanner. In another embodiment, one or more
prisms may split the beam and the split beams may be shuttered, such as
via a mechanical and/or liquid crystal display (LCD) based spatial light
modulation system. In another embodiment, a Spatial Light Modulator (SLM)
may be used to dynamically modify the wave front of the electromagnetic
radiation in order to adaptively focus the beam inside the skin layer. A
grating structure can also be written on the same SLM in order to scan
the electromagnetic radiation over the skin.

[0057] In another embodiment, the beam may be split and transmitted via a
multi-bundle fiber array combined with shutter control at the output of
each of the fibers from the bundle. In one embodiment, optical rastering
can be implemented by the use of a fiber bundle with N fibers and a 1XN
optical switch. The stimulation light can come from either a single
LED/laser source, or it can be the combined output from M LED/laser
sources. By connecting a 1XN optical switch to an N-fiber bundle, the
light can be sequentially directed to any one of the N-fibers in the
bundle by the use of the optical switch.

[0058] In another embodiment, digital light processing technology may be
used to split and direct multiple beams. In one embodiment, a
two-dimensional motion stage, described in terms of an X-Y coordinate
system, may be used to move the electromagnetic radiation source. In some
embodiments, a tilting mechanism may be used to adjust the incident angle
and allow for a greater area for beam delivery. That is, the
electromagnetic radiation source may be moved within a limited
two-dimensional array combined with a tilting mechanism to widen the
effective two-dimensional range of the system.

[0059] Any of the variously described embodiments of systems for inducing
cutaneous sensations via transcutaneously focused electromagnetic
radiation may be integrated within a display, such as a touch screen
display. For example, a system may be integrated within an LCD or organic
LED (OLED) screen. For example, a system may be integrated and associated
with a pixel or cluster of pixels adjacent to an electromagnetic
radiation source or electromagnetic radiation transmission element. The
system may be configured to provide tactile feedback associated with the
display or touchscreen display. In other embodiments, the electromagnetic
radiation source and/or electromagnetic radiation transmission element(s)
may be placed behind a display that is transparent to the electromagnetic
radiation so that the electromagnetic radiation passes through the
display or vias built into the display.

[0060] For example, the electromagnetic radiation may be directed through
the surface of a touch screen display into the finger, fingers, and/or
hand of a user to induce a cutaneous sensation. A system, according to
any of the embodiments described herein, may be integrated into an
interactive display such as on a smartphone, tablet computer, computer
monitor, or television. In such devices, the location or placement of a
finger or other object may be determined by hardware built directly into
the screen and/or software. The location and contact area information may
be utilized by the system to irradiate only when and where tissue (e.g.,
a finger) is present. In addition to location and contact area
information, movement attributes such as speed and direction may be
determined and used by the control system to dynamically adjust the
electromagnetic radiation transmission settings. For example, the
sensations induced by the transcutaneously focused electromagnetic
radiation may simulate a textured surface. The textured surface felt may
be dynamic and/or changeable. The sensations could also be used as
feedback for actions performed, such as a button press. The stimulation
surface may also be a track pad or other dedicated non-display surface
through which the electromagnetic stimulating energy may pass.

[0061] In one embodiment, a system for inducing cutaneous sensations using
transcutaneously focused electromagnetic radiation may be embodied as an
off-display device associated with a second device. For example, a system
may interact with a user's single finger, multiple fingers, or a full
hand. In some embodiments, users may insert a portion of their bodies,
such as a finger, hand, arm, etc. within the stimulating area of the
device. The user, or portion of the user inserted within the system,
could be held immobile or allowed to move. The system may induce
sensations associated with virtual objects such that they feel or provide
simulated sensations associated with corresponding physical objects. In
some embodiments, the portion of the user to be irradiated with
electromagnetic radiation may be decoupled from other surfaces, so as to
limit sensations other than those induced via the transcutaneously
focused electromagnetic radiation.

[0062] In some embodiments, the off-display embodiment may be passive in
the sense that the tissue to be stimulated cannot move to interact with a
display of the object being represented. In other embodiments, the
off-display embodiment may be partially interactive by allowing the
finger(s) and/or hand to move and/or respond within the off-display
system. In such an embodiment, the system may track movement and make
appropriate adjustments to the stimulating beams for appropriate focus.

[0063] In another embodiment, a covering or housing may be secured to a
finger(s) or hand of a user that allows the user to interact with a
display. The covering may prevent the finger(s) or hand from receiving
mechanical stimulation, such as from the surface of the touch screen
display. Electromagnetic radiation may be directed onto the finger pad(s)
of the user via fiber optics and/or other lenses or mirrors within the
covering. The fiber optics may be connected to a remote electromagnetic
radiation source. The covering may allow for interaction with a display
or other interface. The electromagnetic radiation may induce sensations
during the interaction and the covering may limit extraneous sensations
(such as the texture of the display). In some embodiments, the display
may be a computer or phone screen. The display could also be a
holographic or virtual reality display presented in two or
three-dimensions.

[0064] A library of stimulation protocols may dictate the various
sensations that can be induced by the system. Appropriately stimulating
different receptors, axons, dendrites or other excitable tissues with
electromagnetic radiation at the appropriate place on/within the skin and
with the appropriate repetition rates may be used to effectively
replicate tactile stimulation sensations experienced by touching a
physical object. A library may contain the basic components of complex
sensations that, when combined appropriately, are capable of inducing a
wide range, or even all, of the cutaneous sensations, including, but not
limited to, those involving textures, pain, hot, cold, wet, dry, sticky,
etc. Thus, a controller may modify the characteristics of the
electromagnetic radiation to change the pulse width, shape, amplitude,
energy density, duty cycle, frequency, depth, location(s), spot size,
wave shape, modulation characteristics, rasterization patterns and/or
other characteristics of the electromagnetic radiation beam to induce any
of a wide variety of cutaneous sensations. In some embodiments, these
pre-defined cutaneous sensation effects can be combined and mixed
appropriately to create new sensations within predetermined safety limits
to prevent harm to the user.

[0065] The stimulation protocols may include waveforms of various shapes
and patterns. The various pulses delivered are combined into trains
consisting of, but not limited to, square, triangular, trapezoidal, and
sinusoidal shaped pulses. Electromagnetic radiation may be continuously
emitted, pulsed, electronically shuttered, pulse-width modulated (PWM),
and/or otherwise modulated or pulsed. The spot size of the incident
electromagnetic radiation may also be varied to create different sensory
effects. This spot could be dynamically altered by movable lenses and/or
by a variable aperture.

[0066] Obtaining tactile information may be done by a number of different
means. In one embodiment, a system may be configured to obtain tactile
information for replication using an ultrasonic probe. An ultrasonic
probe may be used to gather topographical information of an object, how
compliant an object is, and/or subsurface characteristics of an object.
In some embodiments, a laser may be used to determine the characteristics
of a surface of an object. In some embodiments, a 3-D camera system may
also be used to capture surface characteristics of an object. In another
embodiment, a series of probes mounted on calibrated springs may be
utilized to mechanically determine characteristics of a surface. As the
spring is compressed, its displacement gives the appropriate information
about the object's properties. Additionally, a differential transformer
may be used to measure linear or translational displacements on a
surface.

[0067] In one embodiment, a system, as described herein, may be utilized
by the user to measure physical characteristics of objects and induce
corresponding sensations for the user. For example, an imaging device may
be used to scan the surface of an object. The system may translate the
image into a series of tactile sensations to be induced using
transcutaneously focused electromagnetic radiation. In some embodiments,
characteristics such as color, grey scale, line thickness, temperature,
and the like, may be translated into tactile sensations.

[0068] In one embodiment, a sub-threshold electrical stimulation system
may be combined with transcutaneously focused electromagnetic radiation.
For example, electrodes may be placed near or at the location of the user
where electromagnetic radiation is to be received. The electrodes may be
configured to provide subthreshold stimuli in the general area.
Accordingly, the electrodes themselves may not produce any action
potential in the mechanoreceptors or their afferent axons. The electrical
stimuli may be cyclic at high rates corresponding to the necessary
electromagnetic stimulation. Electromagnetic radiation may be applied in
conjunction with the cyclical electrical stimuli. According to such an
embodiment, since the electrical stimuli provides a sub-threshold
stimulation, the electromagnetic radiation may be used to induce
cutaneous sensations at lower energy densities and may also provide for
greater selectivity of action potentials from Aβ and Aδ neural
fibers that convey tactile information over C fibers that carry pain and
thermal information.

[0069] In one embodiment, the tactile information conveyed by a system as
described herein may be associated with a tactile logo or tactile
signature. A static or dynamic sensation may be incorporated into any
number of applications. For example, a tactile logo may be felt beneath a
visually displayed web page. The logo may not be visually displayed and
only felt by the user. Such functionality could be incorporated in both
on-display and off-display systems as described herein.

[0070] For example, the tactile logo could be generated constantly beneath
the finger every time the finger is in contact with the screen.
Alternatively, the tactile logo may be associated with specific displayed
content, such as, but not limited to, a text, images, and/or animation
delivered to the user, such that when a specific object or text is
touched by the user, the logo is felt. A recognizable tactile logo could
let the user know who is sponsoring a certain web page, that a page is
secure, or in another application without taking up visual space on the
screen. This may be particularly valuable on a mobile phone or other
device with limited screen space. Customers could purchase tactile logos
for inclusion on personal or company web pages, applications, and/or the
like.

[0071] Tactical representations may be encoded similar to black and white
digital photographs. For example, a tactical representation may be
represented by x and y coordinates with amplitude or depth information
encoded at each point. Each point may be called a tixel (tactile image
element). The number of tixels and the range of possible representations
(e.g., bits) for amplitude or depth information may define the resolution
of a tactile representation. Each surface of an object may be represented
by a tactile image or code. With a library of such images the surfaces of
these objects may be represented as a corresponding induced sensation to
the user. In another embodiment, thermal images that show temperature
fields or gradients can be represented as tixels and representations
(e.g., bits) for temperature or temperature gradients may define the
resolution of a tactile thermal representation.

[0072] In many embodiments, the user interface may be a flat surface on
top of which cutaneous sensations are created. In such embodiments, the
surface textural information and an object's shape and compliance may be
conveyed to the user. In another embodiment, an object's temperature and
temperature gradient information may be conveyed to the user. In
embodiments in which a user's hand, finger, or other portions of the body
are free to move in three dimensions, the surface information of a
three-dimensional object may be conveyed.

[0073] A library of cutaneous tactile sensations and effects may be
collected and stored in a control program or a separate memory location.
Additionally, custom or combinations of sensations may be created.
Sensations can be derived from a combination of pre-formed sensations
dynamically calculated in software or stored for subsequent retrieval and
use. Sensations may be based on empirical data, based on physiological
testing, algorithmic data, and/or derived from initial calibration data.
In one embodiment, algorithms used to determine sensations may account
for variables, including but not limited to reflectance, temperature,
finger speed, finger pressure, and tixel data to appropriately deliver
the desired sensation(s).

[0074] In various embodiments, a controller or control system may be
implemented as any combination of hardware, firmware, and/or software.
For example, a controller may be implemented as a field-programmable gate
array (FPGA). In some embodiments, an electronic controller may be
distinct from other components of the system for inducing sensations
using transcutaneously focused electromagnetic radiation. The system may
include microprocessors and other electronic components associated with
displays, touch screens, data storage, data connectivity, memory,
non-transitory computer readable media, etc.

[0075] Some of the infrastructure that can be used with embodiments
disclosed herein is already available, such as general-purpose computers,
computer programming tools and techniques, digital storage media, and
communication networks. A computing device or other electronic controller
may include a processor, such as a microprocessor, a microcontroller,
logic circuitry, and/or the like. The processor may include a
special-purpose processing device such as application-specific integrated
circuits (ASIC), programmable array logic (PAL), programmable logic array
(PLA), a programmable logic device (PLD), FPGA, or another customizable
and/or programmable device. The computing device may also include a
machine-readable storage device, such as non-volatile memory, static RAM,
dynamic RAM, ROM, CD-ROM, disk, tape, magnetic storage, optical storage,
flash memory, or another machine-readable storage medium. Various aspects
of certain embodiments may be implemented using hardware, software,
firmware, or a combination thereof.

[0076] The embodiments of the disclosure may be understood with reference
to the drawings, wherein like parts are designated by like numerals
throughout. The components of the disclosed embodiments, as generally
described and illustrated, could be arranged and designed in a wide
variety of different configurations. Furthermore, the features,
structures, and operations associated with one embodiment may be
applicable to or combined with the features, structures, or operations
described in conjunction with another embodiment. In other instances,
well-known structures, materials, or operations are not shown or
described in detail to avoid obscuring aspects of this disclosure.

[0077] Thus, the following detailed description of the embodiments of the
systems and methods of the disclosure is not intended to limit the scope
of the disclosure, as claimed, but is merely representative of possible
embodiments.

[0078]FIG. 1 illustrates a block diagram of a system 100 for exciting
tissue using electromagnetic radiation from a light source 130, according
to one embodiment. According to various embodiments, a system 100 may
include a control program, 110, a power source 120, a light source 130,
one or more optical components 140 for transcutaneously focusing
electromagnetic radiation from the light source 130 on excitable tissue
150, and a feedback system 160.

[0079] As illustrated, the light source 130, or other electromagnetic
radiation source, may generate pulses of light at appropriate energies
and duration to stimulate excitable tissues, mechanoreceptors, and/or
innervating afferent axons. According to various embodiments, the pulse
duration of the light source 130 may be in the range from 1 μs to 500
ms and stimulation frequency may be in the range from 0 Hz to 1000 Hz.
Other pulse ranges and/or frequency ranges capable of stimulating
excitable tissues may be utilized. In some embodiments, one or more
optical components 140 may be used to focus the light on or within the
excitable tissue 150. The optical components 140, in conjunction with the
light source 130, may be configured to minimize radiation exposure of
non-excitable tissue and/or avoid excessive heating of the excitable
tissue 150. Light emitted by the light source 130 may, directly or
indirectly, excite action potentials to induce sensations corresponding
to tactile sensations, as interpreted by the central nervous system.

[0080] The feedback system 160 may measure skin temperature, pressure from
the user on the system, user movement relative to the system, and/or to
determine effectiveness of various incident energies and points of
stimulation. The feedback system may provide information to the control
program for dynamically adjusting the inducement of cutaneous sensations
via the transcutaneously focused electromagnetic radiation emitted by the
light source 130. The control program 110 may be implemented in hardware,
firmware, and/or software. The control program may communicate with
and/or control the feedback system 160, the optical components 140, the
light source 130, and/or the power source 120.

[0081]FIG. 2 illustrates a simplified embodiment of a system 200 for
delivering electromagnetic radiation 220 focused 245 on a finger 210 of a
user. As illustrated, a wide beam of electromagnetic radiation 220 is
focused by a lens 230 such that the focused electromagnetic radiation
converges at or below the epidermal surface of the user's finger 210.
Only at the focus point 240, is the radiation fluence sufficiently high
to stimulate, directly or indirectly, an action potential within the
finger 210. The electromagnetic radiation may diverge 255 and/or be
absorbed/scattered after stimulating the action potential within the
finger 210.

[0082] According to various embodiments, units of energy may be expressed
in terms of fluence or Joules per square centimeter. In various
embodiments, the electromagnetic radiation 220 used to excite the action
potential may be between 1 mJ/cm2 and 100 J/cm2. For example,
the energy of individual pulses may be between approximately 0.1 and 25
J/cm2. Outside of the focus point 240, the fluence may be
sub-threshold for action potential initiation and of lower fluence,
resulting in less tissue heating. In some embodiments, an actuator may
mechanically rotate, move, vibrate, and/or otherwise direct the
electromagnetic radiation 220. In another embodiment, the electromagnetic
radiation 220 and/or the lens 230 may rotate, move and/or vibrate using
beam steering capabilities due to mirrors, spatial light modulators, or
other optical and/or electrical methods. The actuator may control the
procession of the electromagnetic beam to mitigate collateral tissue
heating.

[0083]FIG. 3 illustrates a simplified embodiment of a system 300 for
delivering multiple electromagnetic radiation beams 320 and 330
transcutaneously coincident, at 340, on a finger of a user. Two beams 320
and 330 are shown in the illustrated embodiment, but any number of beams
may be used. Each of the beams 320 and 330 may have insufficient energy
densities to excite tissue and, thus minimize the energy imparted to
non-excitable tissue. The point of coincidence 340 may include the
combined energy densities of each of the beams 320 and 330 of
electromagnetic radiation. Thus, at the point of coincidence 340, the
energy density may be sufficient to initiate an action potential. In some
embodiments, the size of the focus may be adapted to create different
sensory effects. In some embodiments, the size of the focal spot may also
be dynamically adjusted.

[0084]FIG. 4 illustrates a display 430 associated with a system 420 for
inducing haptic sensations via transcutaneously focused electromagnetic
radiation. In various embodiments, the system 420 may be in communication
with the display 430. Accordingly, a portion 415 of the user 410 within
the system 420 may receive cutaneous sensations induced by
transcutaneously focused electromagnetic radiation. As illustrated, the
system 420 may be a hand enclosure configured to receive a hand of a
user. In such an embodiment, a user may receive cutaneous sensation
associated with images, objects, icons, or the like on the display 430.
In some embodiments, the finger or hand of the user may be immobilized.
In other embodiments, the finger or hand of the user may move within the
system 420 and/or be able to provide responses to the received cutaneous
sensations induced by the system 420. The power supply, light source,
lensing system, and feedback systems may be all housed in the single
enclosure. According to other embodiments, various components may be
housed in multiple enclosures. Further, a user's finger or hand could be
suspended at a distance above a stimulating surface rather than coming
into direct contact with a stimulating surface.

[0085]FIG. 5A illustrates a display screen 520 configured with a system
to induce cutaneous sensations in a user's finger 515 using
transcutaneously delivered electromagnetic radiation. The illustrated
embodiment is an example of an on-display configuration. Display 520
could be part of a mobile device, such as a smartphone or tablet
computer, a stationary device such as a desktop computer, interactive
public display, industrial control station, surgical control station,
and/or other interactive display device. In the illustrated embodiment,
the finger 515 of a user 510 comes into contact with the display 520,
upon which the image is displayed. In some embodiments, the optical
energy may be delivered through the front of the display.

[0086] In one embodiment, a system for inducing cutaneous sensations via
transcutaneously focused electromagnetic radiation may be in the form of
a flat surface adjacent to or opposite a display surface. For example, on
a mobile phone or a tablet computer, the system could be integrated into
a flat surface that is beside, beneath, and/or on the sides of a display
surface. Such an embodiment may allow for tactile interaction with the
content displayed without obscuring any portion of the visual display. A
light source according to any of the various embodiments described herein
may utilize various types of lasers, VCSELs, LEDs, and/or other
high-density focusable light sources.

[0087]FIG. 5B illustrates an accessory component 560 configured to induce
cutaneous sensations in a user's finger 515 via transcutaneously focused
electromagnetic radiation while using a display 525. In the illustrated
embodiment, the electromagnetic radiation may be transmitted through the
accessory device 560 (illustrated as a finger sleeve) into the finger 515
of the user 510. The electromagnetic radiation may originate from a
remote source and be transmitted via a fiber optic cable 565 to the
accessory component 560. In some embodiments, the accessory component 560
may secure the finger 515 suspended away from the walls thereof to avoid
mechanical stimulation due to physical contact with external objects,
such as the display 525.

[0088] Optical components for focusing the electromagnetic radiation
and/or feedback sensors and components may be incorporated into the
accessory component 560. In some embodiments, an interaction mechanism
between the external wall of the accessory component 560 and the display
525 may allow the user to interact with the virtual or distant object
shown on the display 525 and experience the tactile sensations in a
natural manner. For example, the interaction mechanism may utilize a
laser distance finder, capacitive touch screen, an image sensor, a
camera, a 3D or depth camera, and/or an ultrasound echolocation system.

[0089] FIG. 5C illustrates a conceptual representation of an
electromagnetic radiation delivery system 500 including a single
electromagnetic radiation source 574 that may be incorporated into a
finger sleeve or other device, according to certain embodiments. System
500 may include a switch controller 572 coupled to an optical switch 570.
Electromagnetic radiation source 574 may be coupled to optical switch
570. A plurality of fiber optic cables 582 may be bundled in a cable 580.

[0090] An enlarged view of a distal end 578 of cable 580 shows the
plurality of fiber optic cables 582. Optical switch 570 may selectively
direct electromagnetic radiation generated from electromagnetic radiation
source 574 to any one of the plurality of fiber optic cables 582.

[0091]FIG. 5D illustrates a conceptual representation of an
electromagnetic radiation delivery system 590 including a plurality of
electromagnetic radiation sources 574a-574d that may be incorporated into
a finger sleeve or other device, according to certain embodiments. System
590 may include a number of components that are similar to system 500,
and accordingly, similar reference numbers are utilized. System 590 also
includes a fiber combiner 576. System 590 may utilize a plurality of
electromagnetic radiation sources 574a-574d in order to realize an
increase in power output, a decrease in the cost of the system or other
potential advantages.

[0092]FIG. 6A illustrates an embodiment of a stage 615 with a moveable
electromagnetic radiation source 617 for rastering electromagnetic
radiation to transcutaneously excite tissue. A system, according to any
of the various embodiments described herein, may utilize a moveable
electromagnetic radiation source 617 to control where the electromagnetic
radiation is transcutaneously focused. In some embodiments the stage 615
contains the electromagnetic radiation source 617 and optics, while in
others it includes only the optics or only the electromagnetic radiation
source 617. In some embodiments, the stage 615 may be behind a display
610 (or other user interface component such as a track pad or dedicated
haptic feedback surface), while in other embodiments the stage 615 may be
in front of the display 610. In the latter embodiment, the stage 615 may
be substantially transparent to visible light, such that the display 610
is not or minimally impeded. The mechanism for moving the stage 615 may
be mechanically and/or electromagnetically controlled.

[0093] For example, as illustrated in FIG. 6B, the stage 650 may contain
lightweight permanent magnets 652 that would be attracted to or repelled
from certain areas by a grid or array of controllable electromagnets 655.
These electromagnets 655 can reside either on the rear of the display 640
or along a frame around the display 640, so as to not occlude the display
640 for the user. In an embodiment where the electromagnetic radiation
source is not incorporated into the stage 650 itself, the source 660 may
be in the same plane as the stage, but off to the side of the field. The
electromagnetic radiation may be directed from the source to the stage
650 where it is reflected and/or refracted by optical components and
focused into the intended tissue.

[0094] The ability to raster the electromagnetic radiation beam may be
useful for stimulating multiple points when simulating mechanical
stimuli. Any of a wide variety of rasterizing systems, methods, and
patterns may be used. For example, a galvanometer based scanner or beam
splitter with shuttering technologies may be utilized.
Microelectromechanical system (MEMS) based reflection and direction of
the beam may be used to rasterize the beam. In one embodiment, the tip of
one or more laser fibers with external optical lens(es) (i.e., separate
from the delivery fibers) may be attached to the stage 650. The laser
fiber and external optics may be collectively called the laser head. The
plan of the assembly and stage 650 may be parallel to the plane on which
a finger, fingers, hand, or other portion of the body is to be
stimulated. The stage 650 may be moveable in order to reach all areas of
the finger or full hand.

[0095] A controller may move the stage 650 based position information in
the x-y direction. The position of the stage 650 may be determined by
encoders or position sensors 665 on each axis of the stage 650 and/or
near the edges of the display 640. The controller may also periodically
move the beam, such that the procession irradiates a certain location on
the finger pad/hand for only a certain amount of time. The procession of
the beam can be in multiple patterns, all contained within the area
smaller than two-point discrimination, as described above. FIGS. 7A-7C
illustrate three example procession patterns that may be used within a
two-point discrimination region to reduce thermal buildup on the tissue.
FIGS. 7A-7C may also be examples of rasterization patterns used to induce
various cutaneous sensations at desired locations. In such embodiments,
the various points in the patterns illustrated in FIGS. 7A-7C may be
separated by more than two-point discrimination.

[0096] In some embodiments, the same tissue location may be irradiated
repeatedly using different light source parameters, such as, but not
limited to, pulse widths, frequencies, energies and/or waveforms for each
pulse or series of pulses. The control system may track the energies and
exposure time delivered to each spot on the tissue and adjust the pulses
based on the feedback data to induce the appropriate sensations and avoid
injury. If the tissue is moved relative to the light source, there may be
a need to increase the power delivered to the previously unexposed
tissues. Tracking tissue placement relative to the area of irradiation
may allow the control program to deliver the appropriate power to the
tissue to induce the desired sensation.

[0097] FIG. 8 illustrates an electro-optical system 800 for inducing
cutaneous sensations, including an electrical sub-threshold-inducing
device 820 and a system for transcutaneously focusing electromagnetic
radiation according to any of the various embodiments described herein
(not shown). As illustrated, electrodes 830 and 835 leading from an
electrical stimulator 820 may be attached to a finger 815 of user 810.
The electrodes 830 and 835 may be attached away from the area to be
optically stimulated to avoid mechanical stimulation. The sub-threshold
electrical stimulation may utilize any of a wide variety of waveform
shapes, such as square 825, or another waveform, such as sinusoidal,
triangular, trapezoidal, monopolar, and/or bipolar. The electrical
stimulation may be sub-threshold for all or most sensory modalities. It
may be used to reduce the activation threshold necessary to induce
cutaneous sensations using transcutaneously focused electromagnetic
radiation. If the transmembrane potential of the mechanoreceptor, its
afferent axon, or other excitable cells are raised closer to the action
potential threshold, then less electromagnetic radiation may be required
to directly or indirectly initiate the action potential.

[0098] FIG. 9 illustrates a schematic 900 of a user calibration procedure,
according to one embodiment. The energies required to transcutaneously
induce a cutaneous sensation using electromagnetic radiation may differ
for each user. For example, the pigmentation and other intrinsic
characteristics, such as the finger print pattern or skin optical
properties, of each user's skin can be different. Accordingly, in some
embodiments a controller may perform an initial calibration for each user
and/or use.

[0099] A calibration procedure may include imparting energies that should
initially be sub-threshold, followed by successively higher energy
levels. The user may respond by indicating to the control program whether
or not a sensation was felt. FIG. 9 illustrates progressively higher
energy levels as peaks 910, 920, 930, and 940, followed by troughs 915,
925, 935, and 945, respectively. In some embodiments, the control program
may deliver the next, higher energy stimuli only after receiving some
response or after a time period has passed during which a response would
have been expected. A calibration procedure may also be used to determine
the range of fluences that may be used (e.g., the lowest energy that can
be felt and the highest energy density that won't cause harm or be
uncomfortable). The calibration procedure may be used for various
cutaneous sensations, such as tactile and temperature/heating sensations.

[0100] According to some embodiments, a calibration procedure may be based
on continuously delivering groups of pulses that step up to higher energy
levels after predetermined periods of time. Each group of pulses may
include a priming pulse that precedes a train of identical pulses. The
priming pulse may reduce sensation latency at the new energy level.

[0101] Part of the calibration procedure may account for feedback
variables, such as skin temperature, skin tone, incident pressure on
stimulation surface, finger speed, and duration of previous exposure. In
some instances, when using multiple fingers it is possible that different
fingers would have different calibration results. In such cases, the
program or controller may keep track of the fingers individually,
delivering the appropriate energies to each finger (or other region of
the body).

[0102]FIG. 10 illustrates a block diagram of a system 1000 for inducing
cutaneous sensations via transcutaneously focused electromagnetic
radiation, including a thermal feedback system 1050. As illustrated, an
electromagnetic radiation source and/or optics 1040 may impart energy via
a beam 1020 to tissue 1015. The energy may be the stimulus for direct or
indirect excitation of mechanoreceptors and/or neural or other excitable
tissue. Output from the electromagnetic radiation source may be adjusted
based on tissue temperature to deliver the appropriate energy to create
sensation. At certain wavelengths the byproduct of the light beam
incident on the tissues may be thermal energy buildup (heat). A thermal
feedback system 1050 may measure the radiation from the tissues to
determine the temperature of the tissues. If the tissues become too hot,
then the controller 1030 may lower the intensity of the light beam output
by the system.

[0103] Any type of temperature sensor or detector, such as a thermistor,
may be used to determine the temperature of the finger. The feedback
system 1050 may be in physical contact with the tissue 1015. In another
embodiment, the thermal feedback system 1050 may be a non-contact sensor.
A sensor may be placed to the periphery of the surface so as to not
distort or impede the passage of the stimulating light. Sensors may be
integrated into the surface or display and/or made from materials
transparent to the necessary wavelengths of stimulating light and, in the
case of a visible display, visible light. As with the thermal imager
above, the temperature data may feed the algorithm(s) that adjust the
stimulation output appropriately.

[0104] The temperature of the stimulating surface may be controlled. For
example, in an embodiment where the tissue is in contact with a surface
through which stimulation passes. Such an embodiment may not have a
temperature feedback system. The surface temperature could be actively
heated (or cooled) through any number of mechanisms including, but not
limited to, embedded electric heating filaments, thermoelectric heat
pump, IR radiation, or directing the heat from other processes such as
the computer or graphics processor.

[0105]FIG. 11 illustrates a system 1100 for transcutaneously inducing
cutaneous sensations integrated within a peripheral device 1153 of a
computer. A sensation-inducing system according to any of the various
embodiments described herein may be incorporated into any of a wide
variety of peripheral control devices, such as the illustrated computer
mouse 1153. The finger 1110 used to control the mouse 1153 may have a
finger pad 1115 on a control surface 1152. A system configured to induce
cutaneous sensations using transcutaneously focused electromagnetic
radiation may be integrated with the control surface 1152. A pressure
sensitive feedback mechanism may be used to modulate the imparted
stimulation in proportion to the pressure exerted by the user. In another
embodiment, the finger pad 1115 may be held away from any physical
surface similar to the concept described in conjunction with FIG. 5B.

[0106] FIGS. 12A-C illustrates three embodiments for incorporating a
system for inducing cutaneous sensations via transcutaneously focused
electromagnetic radiation within a surface 1220. As illustrated in FIG.
12A an electromagnetic radiation source 1250 may be positioned beneath a
surface 1220, such as a touch pad, track pad, or display. For example,
the surface 1220 may be part of an off-display embodiment where there is
no visual information conveyed, or it could be a visible display that is
interactive both for vision and touch. In an embodiment in which the
surface 1220 is a display, the display could be any number of different
display types including, but not limited to, LCD, LED, OLED, AMOLED,
e-ink, array of controllable mirrors, or digital micromirror device. The
display may be substantially transparent to the electromagnetic radiation
used for stimulation.

[0107] Alternatively, the electromagnetic radiation from the source 1250
may be transmitted via channels or vias in the surface 1220. FIG. 12A
illustrates an embodiment in which a source 1250 is directly beneath the
surface 1220. FIG. 12B illustrates an embodiment in which electromagnetic
radiation from the source 1250 is directed by an optical scanner 1255
through the surface 1220 and onto/into a finger 1210. FIG. 12c
illustrates an embodiment in which electromagnetic radiation from a
source 1250 is directed through an optical scanner 1255 to a series of
reflective mirrors 1260 with angled surfaces 1265 in order to reflect the
electromagnetic radiation onto/into the finger 1210 of a user. The
optical scanner 1255 may be configured to irradiate multiple points on
the finger to induce cutaneous sensations.

[0108]FIG. 13 illustrates an example of a display 1300 with an integrated
system 1320 for inducing cutaneous sensations via transcutaneously
focused electromagnetic radiation. As illustrated, a display surface 1310
may include a series of LEDs or other visible light sources 1327
clustered on the display as pixels 1325. Electromagnetic radiation
sources for inducing cutaneous sensations via transcutaneously focused
electromagnetic radiation may be integrated within the display surface.
In some embodiments, the electromagnetic radiation sources may be formed
on the same substrate. The electromagnetic radiation sources may include
LEDs, laser diodes, IR light sources, VSCELs, and/or other suitable
sources. The proximity of the sensation inducing sources to the finger of
a user may reduce the power requirements required to induce sensations. A
digitizer or other technology may be used to sense the location and area
of contact of a user's finger (or fingers, hand, portion of the body,
etc.). Limiting stimulating emissions to those areas where the target
tissue is touching the screen may minimize energy waste.

[0109] It may be desirable to minimize or eliminate sensation-inducing
electromagnetic radiation in any location except for a desired location
and area of contact (i.e., where a finger is). Certain wavelengths of
electromagnetic radiation may cause damage to the eye at high
intensities, such as the corneal surface, lens, or retina. FIG. 14A
illustrates a schematic of a relatively thin fluid layer 1445 on a
surface 1440 configured to prevent stray electromagnetic radiation
emissions. The fluid layer 1445 may absorb, reflect, or refract
sensation-inducing electromagnetic radiation and prevent it from
negatively impacting a user. FIG. 14B illustrates a finger 1410
depressing the relatively thin fluid layer 1445 with a finger pad 1415.
The depression 1450 may vacate a sufficient amount of the fluid to allow
the sensation-inducing electromagnetic radiation to penetrate the finger
pad 1415. The fluid layer 1445 may allow visible light to pass with
minimal attenuation and optical distortion.

[0110] FIGS. 15A-15C illustrate an embodiment of a display 1510 with an
integrated system for inducing cutaneous sensations via transcutaneously
focused electromagnetic radiation, utilizing an array of lenslets and
VCSELs 1513. As illustrated in FIG. 15A, a touch screen display 1510 may
include one or more functional layers 1511, 1512, and 1513 manufactured
as a single physical layer or as discrete physical layers. A touch
sensitive layer 1511 may be configured to receive touch inputs from a
finger or fingers of a user. A transmissive or reflective Spatial Light
Modulator (SLM) Layer 1512 may be configured to modulate visible light
and/or other electromagnetic radiation. A third layer 1513 may include an
N×N array of lenslets with integrated VCSELs. Each lenslet may be a
discrete lens aligned with a VCSEL in order to collimate the upward
emitting VCSEL output.

[0111] As illustrated in FIG. 15B, the collimated electromagnetic
radiation may then traverse the transmissive spatial light modulator
layer 1512 where the wave front 1550 could be arbitrarily modulated prior
to being transmitted through the touch sensitive layer 1511. The
electromagnetic radiation from the VCSELs may be used to induce cutaneous
sensations by transcutaneously focusing the electromagnetic radiation on
a user's finger(s) 1510. In various embodiments, the electromagnetic
radiation may be transmitted through the display/touch screen layer(s)
1511. For instance, if the wavelength of the sensation-inducing
electromagnetic radiation is about 1300 nm, the electromagnetic radiation
may be transmitted with minimal loss through silicon. Furthermore, in
various embodiments, the location of the finger 1510 on the touch screen
1511 may be detected by the touch screen and used by the controller of
the system for inducing cutaneous sensations via transcutaneously focused
electromagnetic radiation.

[0112] In various embodiments, the SLM layer 1512 may be used to optimize
focusing on the surface or inside human tissue through close-loop
feedback control. For example, the wave front of the electromagnetic
radiation may be modulated in a systematic fashion. After each alteration
of the wave front, a user may provide feedback based on the strength of
the tactile sensation. Convergence to an optimum wave front may be
achievable after a number of iterations during an initial calibration
phase. An adaptive focusing scheme may be used to increase focal
intensity by several folds. The focused/modulated electromagnetic
radiation may be scanned over the finger by imposing a dynamically
changing phase grating pattern using the SLM layer 1512. SLM based
optical scanning has the advantage of size and speed, eliminating the
need for mechanical scanner and the inertia associated with it.

[0113] Additionally, as illustrated in FIG. 15c, the SLM layer 1512, may
impose a grating or dot pattern 1555 for scanning stimulation spots and
rasterization schemas. The grating 1555 may be formed as a distinct layer
in addition to the SLM layer 1512, or in place of the SLM layer 1512.
Additionally, it may be possible to create a variety of static patterns
using diffractive optical elements and/or selectively activating pixels
of the SLM.

[0114] The above description provides numerous specific details for a
thorough understanding of the embodiments described herein. However,
those of skill in the art will recognize that one or more of the specific
details may be omitted, modified, and/or replaced by a similar process or
system.